The present invention relates to an improved zoom lens fixing mechanism, particularly a zoom lens fixing mechanism which is easy to assemble with a simple and automatic procedure for the lowering of production cost and improvement of production efficiency.
Conventionally, a zoom lens fixing mechanism, as shown in FIG. 4, comprises a cam sleeve (31), a fixing sleeve (32), a front lens holder (33), a back lens holder (34), four rollers (38, 39, 40, and 41), and a back cover (37). After fitting of the front lens holder (33) to the rear lens holder (34), an end of the front lens holder (33) is placed in the fixing sleeve (32), and then to the cam sleeve (31) for assembly, The cam sleeve (31) has a long slot (311) and three cam slots (312) on its body, and the fixing sleeve (32) has a cam slot (321) and three long slots (322) corresponding to the long slot (311) and the cam slots (312) of the cam sleeve (31).
The front lens holder (33) has three screw holes (35) and the rear lens holder (34) has a screw hole (36) corresponding to the cam slot (321) and long slots (322) of the fixing sleeve (32) and the long slot (311) and cam slots (312) on the cam sleeve (31). Before fitting of the roller (41) to the screw hole (36) on the rear lens holder, the roller (41) must be caused to pass the long slots (311) on the cam sleeve (31) and the cam slot (321) of the fixing sleeve (32). On the other hand, the rollers (38, 39, and 40) must be caused to pass the three cam slots (312) on the cam sleeve (31) and the three long slots (322) on the fixing sleeve (32) before they are fitted to the three screw holes (35) on the front lens holder (33), while the roller (41) passes through the long slot (311) of the long sleeve (31) and the cam slot (321) on the fixing sleeve (32), and is fitted to the screw hole (36) on the rear lens holder (34). Assembly of the zoom lens fixing mechanism is finally completed by fitting of the back cover (37). In such a structure, the front and rear lens holders (33 and 34) can be moved in opposite directions by moving of the rollers (38, 39, 40 and 41) in the long slots (311 and 322) and the cam slots (312 and 321). However, as described, the rollers (38, 39, 40 and 41) must be precisely fitted to the long slots (311 and 322) and the cam slots (312 and 321). However, there is a resistance there. If the lens holder (33 or 34) is on a slant, the long slots (311 and 322) cannot align with the cam slots (312 and 321), and the rollers (38, 39, 40 and 41) cannot be fitted to the respective screw holes (35 and 36). Therefore, a lot of time and labor will be wasted in the assembly, and automatic assembly procedure can be implemented, and its production cost cannot be lowered.
In view of the above defects, the inventor has created an improved zoom lens fixing mechanism which makes use of a notch/opening at the end of each of the cam slots and long slots such that first, the rollers can be fitted to the front and rear lens holders, secondly, the rollers are then run into the cam slots and long slots respectively, and finally the back cover is fitted to prevent from falling out of the rollers. With such a structure, the assembly procedure is improved, an automatic assembly process can be implemented, waste of time and labor is minimized, and production cost is lowered.